Hands on practices on products and applications. · 2017. 5. 9. · data fusion (SNAP) 11 lick on „Graph uilder” icon to open empty graph. 1 1 Right-click on the empty canvas

Hands on practices on products and applications.

Karol ParadowskiSenior Specialist

Institute of Geodesy and CartographyModzelewskiego 27 Street

02-679 WarsawPoland

[email protected]

1Training course on the use of satellite products for drought monitoring and agro-meteorological applications.

24-28 April 2017, Venue, OSMZ HQ Budapest (Hungary)

mailto:[email protected]

http://www.igik.edu.pl/

Presentation overview

• Download Sentinel-1 and Sentinel-2 data

• SNAP download

• Exercise 1 – Sentinel-1 preprocessing and data fusion (SNAP)

• Sen2Cor download

• Exercise 2 – Sentinel-2 atmospheric correction and NDVI index (Sen2Cor, SNAP)



Download Sentinel-1 and Sentinel-2 data

Training course on the use of satellite products for drought monitoring and agro-meteorological applications.24-28 April 2017, Venue, OSMZ HQ Budapest (Hungary)

3

https://scihub.copernicus.eu/

Open Hub

https://scihub.copernicus.eu/


4

1


2





6

1 2



7

1

2


SNAP: Sentinel Application Platform

8

http://step.esa.int/main/download/


Exercise 1 – Sentinel-1 preprocessing and data fusion (SNAP)

9

-> File-> Import-> SAR Sensors-> SENTINEL-1

Navigate to first of three Sentinel-1 data folder, select „manifest.safe” and confirm with„Import Product”button.



10

In „Product Exporer” panel navigate to „Bands” and double-click on „Intensity_VV” to visulize the data with VV polarization.

1

1

In „Colour Manipulation” panel click on „Switch to logarithmic display” and use black, grey and white sliders to stretch image histogram.

2

2

Data navigation panel


Select Sentinel-1 image from drop-down list of open layers.


11

Click on „Graph Builder” icon to open empty graph.

1 1

Right-click on the empty canvas and navigate to „Subset” tool (Add -> Raster -> Geometric -> Subset). A new TAB appears below the canvas.

3

3

2

2



12

In the same way as „Subset” tool add „Speckle-Filter”, „Calibration” and „Terrain-Correction” tools to the canvas.

o Speckle-Filter• Add -> Radar -> Speckle Filtering ->

Speckle-Filtero Calibration

• Add -> Radar -> Radiometric -> Calibration

o Terrain-Correction• Add -> Radar -> Geometric -> Terrain

Correction -> Terrain-Correction

Right-click on the canvas and click „Connect Graph” or connect tools manually by dragging arrows - starting from the right border of each element



13

Open „Subset” tab and define in pixel coordinates upper left corner (X, Y) and size (Width, height) of the desired subset. If „Source Bands:” window is empty simple switch between different tabs to refresh the view. Select two Intensity layers only (with Ctrl button).

Open „Speckle-Filter” tab and define Filter (e.g. Gamma Map) and Filter Size X and Y (e.g. 7). Select two Intensity layers only (with Ctrl).



14

Leave „Calibration” tab options without changing anything.

In „Terrain-Correction” tab change “Image Resampling Method” to „NEAREST_NEIGHBOUR” and “Map Projection” to desired projection.



15

Open „Write” tab and define processed file name (you can leave it default), file format (BEAM-DIMAP as default), and saving location.

Click on „Save” button to save created Graph and hit „Run” to execute workflow. The processed image will appear in „Product Explorer” window.

Repeat the procedure to generate preprocessed subsets for two other data sets from different acquisition dates:• import Sentinel-1 data into SNAP• use „Graph Builder” to load and execute

previously saved workflow.



16

Generated Sentinel-1 subsets for three different acquisition dates.

Navigate to:-> Radar-> Coregistration-> Stack Tools-> Create Stackto open stack creation tool.



17

In „1-ProductSet-Reader” tab use plus symbol to open „Add Product” dialog. Navigate to and select three Sentinel-1 subsets (with Ctrl button). Press „ok” button to add files to the list.



18

In „2-CreateStack” tab change „Resampling Type:” to „NEAREST_NEIGHBOUR” and „Output Extents:” to „Minimum”.

Go to „3-Write” tab and modify (or leave default values) product name and output directory. Execute tool by pressing „Run” button.



19

Right-click on the newly created stack and select „Open RGB Image Window”.

From drop-down list select VV bands (three different dates) for red, green and blue and press „OK” to create RGB composition.



20

A new “Image Window” will appear with RGB composition.

If needed, adjust histogram stretching for each layer (red, green, blue)



21

Make sure that the stacked image is selected in „Product Explorer” window.

Navigate to:-> File-> Export-> GeoTIFFto open „SNAP –Export Product” tool.

Specify file name and location and press „Export Product” button.


Sen2Cor: Sentinel-2 Level 2A Atmospheric Correction Processor

22

http://step.esa.int/main/third-party-plugins-2/sen2cor/


Exercise 2 – Sentinel-2 atmospheric correction and NDVI index (sen2cor, SNAP)

23

Sentinel-2 MSI – Level-2A Prototype Processor Installation and User Manual

CHAPTER 3 – CONFIGURATION AND INSTALLATION (page 31)

• Setting up the Runtime Environment (Anaconda Upgrade/Installation)

o http://continuum.io/downloads

• Sen2Cor Installation

o In the command line utility navigate to the sen2cor-2.3.1 folder, type

“python setup.py install” and follow the instructions. The setup will

install the Sen2Cor application and all its dependencies under the

Anaconda python distribution.


http://continuum.io/downloads


24

• Sen2Cor installation script will use internet connection to download all needed packages.

• User will be asked to press „y” and „Enter” to finish the configuration of environment settings and

confirm location of sen2cor home directory (which will store e.g. sen2cor configuration file).



25

• Use „L2A_PROCESS --help” command to

display help screen with possible

options.



26

In case of environment variables error (on Windows OS) use following commands to set them correctly:

• SET SEN2COR_HOME=C:\Anaconda2\Lib\site-packages\sen2cor-2.3.1-py2.7.egg\sen2cor

• SET SEN2COR_BIN=C:\Anaconda2\Lib\site-packages\sen2cor-2.3.1-py2.7.egg\sen2cor

If needed adjust both paths to point to the sen2cor folder within Anaconda installation folder.



27

• To include DEM data in data correction go to the sen2cor home folder (usually in user’s Documents

folder, e.g. „C:\Users\<user-name>\Documents\sen2cor”) and in the „cfg” folder open L2A_GIPP.xml

file with appropriate editor (like Notepad++).

• In the line with „DEM_Directory” tags change „NONE” to any other name (e.g. „DEM”).



28

To start data processing use the following command:

L2A_PROCESS <unzipped image data folder path> <optional parameters>

e.g.

„L2A_PROCESS D:\S2A_MSIL1C_20170329T095021_N0204_R079_T33TYN_20170329T095024.SAFE

--resolution 10”

S2A_MSIL1C_20170329T095021_N0204_R079_T33TYN_20170329T095024.SAFE

S2A_MSIL2A_20170329T095021_N0204_R079_T33TYN_20170329T095024.SAFE

INPUT FOLDER:

OUTPUT FOLDER:



29

In SNAP navigate to:-> File-> Import-> Optical Sensors-> Sentinel-2-> S2-MSI-L2A

Navigate to processed Sentinel-2 main data folder, select„MTD_MSIL2A.xml” file and use „Import Product”.



31

In „Product Explorer” window right-click on the newly added data and select „Open RGB Image Window” tool.

In „Select RGB-Image Channels” window select „B4” band as red, „B3” as Green and „B2” as Blue to create „Natural Colors” composition. Confirm with „OK”.

A new „Image Window” will appear.



32

If needed, manipulate with sliders for Red, Green and Blue bands in the „Colour Manipulation” panelto strech thehistogram.



33

From menu „Raster” select „Band Maths...”.

In „Band Maths” dialog define name (e.g. „NDVI”) and select „Edit Expression...” button.

In „Band Maths Expression Editor” define expression as: „(B8 – B4)/(B8 + B4)” and press „OK”.

Confirm with „OK” in „Band Maths” window.



34

A new „Image Window” with calculated NDVI in grey scale will appear.

Switch to „Pixel Info” tab to inspect NDVI values updated from the current cursor position.



35

In “ColourManipulation” panel switch to “Table” view and set red, yellow and green colors in “Colour” column.

Go to “Sliders” view and adjust histogram to improve clarity of the data.



36

In menu “Window” select “Tile Horizontally”.

In “Navigation” tab make sure that both synchronize views and cursor positions buttons are selected.



37

Use on-screen navigation buttons to inspect the data.


Thank you for your attention.

38

Karol ParadowskiSenior Specialist

Institute of Geodesy and CartographyModzelewskiego 27 Street

02-679 WarsawPoland

[email protected]


mailto:[email protected]

http://www.igik.edu.pl/